This invention relates to back and front spotfacing and counterboring tools, and more particularly to an improved such tool having a fluid pressure actuated tool bit which is automatically pivoted between operative and inoperative positions. Moreover, this invention relates to a novel method of utilizing a pressurized coolant fluid for automatically actuating the tool bit of an improved tool of the type disclosed herein.
There are currently available in the marketplace a variety of spotfacing and counterboring tools having tool bits which are pivotal relative to the tool body between inoperative positions in which they are housed within recesses within the tool body, and operative positions in which they project outwardly from the tool bodies into work cutting positions. In my pending U.S. patent application Ser. No. 08/775,576 this movement of a tool bit between operative and inoperative positions is effected by a fly wheel which is carried by the tool body; and in my U.S. patent application Ser. No. 08/953,453, this operation is effected by a spring-loaded actuating ring which is rotatably briefly relative to the supporting tool body thereby to effect movement of the associated tool bit each time the rotation of the tool body is reversed. Also as noted in my application Ser. No. 08/953,453, there are several U.S. patents which disclose tools in which the associated cutter elements are moved between operative and inoperative positions by virtue of engagement of a thrust element on the tool with the surface of the workpiece that is to be machined.
In addition to the above-noted tools there also is a U.S. patent Ser. No. 3,572,182, which teaches the manipulation of the cutter blade of a cutting tool by use of a supply of compressed air or hydraulic fluid that is operatively connected to the cutter to manipulate its associated cutter blade.
Among the numerous problems associated with such prior art devices is the fact that much of the movement of the cutter bit relative to the associated cutter body relies upon the rotation of the tool body to produce the desired manipulation of the cutter bit or blade. Thus, any failure of any of the parts that mechanically transmit the rotation of the tool body to the mechanism which manipulates the cutter bit, will result in unsatisfactory manipulation of the cutter bit. Although this is a lesser problem in connection with a cutter bit of the type disclosed by the above-noted U.S. Pat. No. 3,572,182, such fluid pressure operated devices, nevertheless, are rather expensive to construct and install, and require separate valving means used exclusively for controlling the flow of air pressure to and from the associated tool.
It is an object of this invention, therefore, to provide an improved fluid actuated spotfacing and counterboring tool which eliminates the need for employing as part of the tool separate valving means for controlling the flow of operating fluid to and from the tool.
Another object of this invention is to provide an improved spotfacing and counterboring tool of the type described which utilizes a fluid under pressure for moving an associated tool bit from an inoperative to an operative position, and which relies solely upon a spring mechanism for returning the tool bit to its inoperative position.
A further object of this invention is to provide a novel method of utilizing existing pressure operated coolant systems for effecting manipulation of the associated tool bit of an improved tool of the type described herein.
Still other objects of this invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.